Three prisoners at the detention facility in Guantanamo Bay, Cuba, have hanged themselves in what the U.S. military is calling an act of "asymmetric warfare."

The men used their clothes and bed sheets, and left behind notes written in Arabic, the military said. They are the first confirmed deaths at the compound. Prisoners have attempted suicide in the past.

"Two Saudis and one Yemeni, each located in Camp 1, were found unresponsive and not breathing in their cells by guards," said a statement issued by Joint Task Force-Guantanamo on Saturday.

"Medical teams responded quickly and all three detainees were provided immediate emergency medical treatment in attempts to revive them. The three detainees were pronounced dead by a physician after all lifesaving measures had been exhausted," the statement said.

"This was clearly a planned event, not a spontaneous event," said Rear Adm. Harry Harris, commander of Joint Task Force-Guantanamo.

He described the men, whose names were not released, as committed jihadists captured on the battlefield. "I believe this was not an act of desperation, rather an act of asymmetric warfare waged against us," Harris said.